Coast FIRE

What Coast FIRE means

Coast FIRE is a benchmark based on whether invested assets reach a modelled target without further contributions under the scenario’s return and inflation assumptions.

People sometimes use the concept to model changes such as:

• Taking a lower-stress job
• Going part-time
• Starting a business that may pay less at first
• Taking a career break

The benchmark is not a statement that a person can stop contributing or that any change is suitable. The numerical result changes when its assumptions change.

The basic intuition

Coast FIRE is a time-and-compounding story:

• Early on, contributions matter most
• Later, portfolio growth matters more

Coast FIRE is the transition point between those phases.

How to model Coast FIRE

A useful Coast FIRE model needs:

1. A realistic starting net worth
2. Reasonable investment return and inflation assumptions
3. A clear change in cash flow rules after that point

In Plan in Decades you can model this by:

• Adding a milestone for Coast FIRE
• Reducing contributions after that milestone
• Comparing that path with the original scenario

Coast FIRE is sensitive to assumptions. Treat it as a numerical benchmark within the scenario, not a forecast, recommendation, or guarantee.